Exercise machine



FIG. 1 is a front and right side perspective view of an exercise machineshowing my new design;

FIG. 2 is a left side elevational view, the right side view being amirror image thereof;

FIG. 3 is a top plan view;

FIG. 4 is a bottom plan view;

FIG. 5 is a front elevational view; and,

FIG. 6 is a rear elevational view.

The ornamental design for an exercise machine, as shown and described.